Electromagnetic device



Patented May 12, 1942 UNITED STATES PATENT ()FFICE ELECTROBIAGNETICDEVICE Francis M. Joseph, Cliflside Park, N. J., assignor to BendixAviation Corporation, South Bend, Ind., a corporation of DelawareApplication January 23,1941, Serial No. 315,705

2 Claims.

This invention relates to electromagnetic devices, and particularly toelectro-magnetic devices of the solenoid class, in which the magneticcircuit includes a closeable gap at a point within the coil or coils ofWire through which the energizing current passes.

An object of the invention is to provide an electro-magnetic device, ofnovel construction, for the actuation of a partto be shifted from oneposition to another. or other control element of an internal combustionengine or other machine, it is probable that the operation thereof mayinvolve a splashing or seepage of oil or liquid fuel into the interiorof the electromagnetic device, and a subsequent leakage of such liquidsfrom the device, and onto the surfaces of adjacent apparatus, to thedetriment of the latter. Another possibility is the entry of explosivevapors, creating a hazard because of possible contact with switchelements, or with sparks emanating from such switch elements. Such ahazard is guarded against in the present invention; one of the objectsof this invention being to provide an electromagnetic device thatincludes a liquid-tight and vapor-tight chamber, with the switchelements housed therein and thereby protected against contact with anyfluid other than ordinary air.

Another object of the invention is to provide,

in a device having a fluid-tight, switch-contain- U by reason of theresilient nature of the arms I3 ing chamber, a second chamber containingthe actuating means for the switch elements of said first-named chamber,and a sealing wall interposed between said two chambers to preventpassage of fluid from one to the other, but without interfering with thetransmission of motion be Another object is to provide means formainsaid taining fluid circulation in said second chamber,

thus rendering impossible the development of a fluid lockmeaning by thisterm any condition of fluid accumulation which might interfere with thefree operation of the movable parts of the device.

A further object is to provide a novel control of the flow of current toan electro-magnetic device.

Another object is to provide current flow control means including switchmechanism and switch actuating means of novel construction, and having anovel mode of operation.

These and other objects of the invention will become apparent frominspection of the following specification when read with reference tothe If such a part is a valve' accompanying drawing wherein isillustrated the preferred embodiment of the invention. It is to beexpressly understood, however, that the drawings are for the purpose ofillustration only, andare notdesigned as a definition'of the limits ofthe invention, reference being had to the ap pended claims for thispurpose.

In thedrawing,

Fig. l is a longitudinal sectional view of a device embodying theinvention;

Fig. 2 is an end view, from theright of Fig. 1, after removal of. thecover plate at said righthand end;

Fig. 3 'is a transversesectional view along line 33 of Fig. 1; i

Fig. 4 is a diagram of the control circuit, including a perspective viewof the switch elements; and -Fig. 5 is a perspective view of theplunger, 01'

movable magnetic element, together with the plunger rod.

In the drawing the source of current is shown at ll, (Fig. 4) thesolenoid winding at l2, the novel switch elements at I3 and I4, and aconventional switch at 15. The latter may be a toggle switch or anyother common type of manually operable switch, while the switch l3, I4is to be automatically operable. To this end its contacts 16, I! arenormally pressed together threaded at itsopen end to receive a closureplatev 24 and an annular nut 26 to hold the closure plate in position.The closure plate 24 has a central opening to receive magnetic element21, the latter having a lip expanded against the opening of the platefor fixation thereto. The element 27 extends inwardly in concentricrelation to the coil l2 and constitutes the fixed polepiece of themagnetic circuit of the solenoid; the movable pole-piece being shown at28. This movable pole-piece (plunger) 28 has pinned thereto (at 29) arod 3| of non-magnetic material, and at its opposite end has a threadedbore to receive the threaded shank 32 of a stud 33 which terminates in ahead 34 adapted to move to the left (from the position shown in Fig, 1)along with the plunger 28 in response to passage of current throughwinding l2 and the resultant closure of the gap in the magnetic circuit;the said gap in the magnetic circuit being normally maintained by thepressure of yieldable spring 36 (seated in the counterbore of pole-piece21) upon the shoulder 31 adjacent the tapered part 38 (see Fig. 5) ofthe plunger 28.

When the head 34 is moved to the left it strikes against, and exertspressure upon, the interposed tab 4| of the current conducting arm l3;and this leftward pressure serves to separate the contact 16 from thecontact [1, in the manner indicated in Fig. 4. The coil energized,however, although with lower energy consumption due to the shunt circuitby way of resistor 23; therefore the rod 3| and the valve (not shown) orother part to be actuated thereby, will be held in the actuatedposition. (As shown in Fig. 1, resistor 23 is a coil superimposed oncoil l2.) Upon de-energization of the coil I2 (by opening switch 15) themagnetic flux drops almost instantly to zero, and spring 36 instantlyreturns the plunger 28 and stud 33 to the positions shown in Fig. 1,whereupon the initially stressed resilient arm l3 springs. back towardarm 14 and thus re-engages the contact H5 with the contact [1; but nocurrent flows therethrough, as switch 15 is now open.

The novel means for maintaining the switch chamber 5| fluid-tight isshown as including a flexible sealing member 52 clamped at its peripherybetween the coil housing 2| and the switch housing 53, while its centralportion 54 is clamped between .the end of plunger 28 and a shoulderformed on the stud 33 at the point where the threaded shank 32 mergesinto said stud. Between this central portion 54 and the peripheralportion there is suiiicient slack in the sealing diaphragm 52 to preventthe development of any substantial stress or strain as the central partof the diaphragm moves back and forth with the remainder of the plungerand stud assembly. As the threaded shank 32 is shorter than the threadedbore of the plunger 28, the stud 33 can be screwed in far enough tobring its shoulder tightly against the diaphragm 52 at the point ofengagement of said diaphragm with the end of the plunger. Thus there isestablished a positive barrier to the passage, into the switch cham ber5l, of any liquid or vapor that may have found its way into the annularspace around the plunger 28. In lieu of passing into the chamber 5| suchliquid of vapor will eventually pass back to the outer (left-hand) endof the unit by way of the longitudinally extending grooves 56 (see Fig.5), thus returning to the interior of the intake manifold or otherchamber of the engine (or other machine) on which the housing 2| ismounted, and in which is contained the valve or other part (not shown)to be actuated by the plunger rod 3|.

The winding I2 and resistor 23 are shown as provided with terminal postsH, 12 and 13 passing through openings in the parallel ends of thehousings 2| and 53, and through openings in the [2 remains peripheralportion of diaphragm 52 and spacer ring 14; the posts H, 12 and 13 beinginsulated from all these parts by means of suitable nonconductingbushings l6 and I1. Terminals ll, 12 and 13 are fixed to the head ofspool 22 in any suitable way, as by being molded therein; and as theseterminals have threaded ends to receive suitable nuts 18, I9 and 80, itwill be seen that the tightening of these nuts will apply furtherclamping pressure to the parts, including the periphery of the sealingelement 52. A boss 8| on housing 53 is provided with an opening 82through which passes the wire that makes electrical connection betweenpost 13 and the source ll.

What is claimed is:

1. In a device of the character described, a spool of insulatingmaterial, a plurality of current conducting terminal posts embeddedtherein, a pair of windings on said spool, one of which is electricallyconnected between two of said posts, the other winding being connectedbetween one of said first two posts and a third post, means normallyestablishing direct electrical connection between said two first-namedterminal posts, thereby short-circuiting said first-named winding, uponcurrent flow to one of said two first-named posts, by way of said thirdpost and said second-named winding, means for causing such current flow,circuitbreaking means responsive to such current flow to break thedirect electrical connection between two first-named terminal posts, andthus divert the current flow to a path which includes said first-namedwinding and places said first-named winding in series connection withsaid second winding, a housing for said windings and spool, and a secondhousing for said circuit-breaking means, said two housings being heldtogether by means including said terminal posts.

2. In a device of the character described, a spool of insulatingmaterial, a plurality of current conducting terminal posts embeddedtherein, a pair of windings on said spool, one of which is electricallyconnected between two of said posts, the other winding being connectedbetween one of said first two posts and a third post, means normallyestablishing direct electrical connection between said two first-namedterminal posts, thereby short-circuiting said firstnamed winding uponcurrent flow to one of said two first-named posts, by way of said thirdpost and said second-named winding, means for causing such current flow,circuit-breaking means responsive to such current flow to break thedirect electrical connection between two first-named terminal posts, andthus divert the current flow to a path which includes said first-namedwinding and places said first-named winding in series connection withsaid second winding, a housing for said windings and spool, and a secondhousing for said circuit-breaking means, a fluid seal between saidhousings, said two housings and said fluid seal being held together bymeans including said terminal posts.

FRANCIS M. JOSEPH.

